Flat heat pipe

ABSTRACT

An exemplary flat heat pipe includes a cover, a wick structure and a restricting plate. The cover defines a receiving chamber therein. The wick structure is received in the receiving chamber. The restricting plate is received in the receiving chamber and opposite ends thereof abut against opposite inner surfaces of the cover to divide the receiving chamber into two passages. The restricting plate divides the wick structure into two wick portions, the wick portions are adhered on lateral surfaces of the restricting plate and located at lateral sides of two passages, respectively.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to heat transfer apparatuses and, more particularly, to a flat heat pipe with enhanced heat dissipation efficiency.

2. Description of Related Art

Generally, flat heat pipes can efficiently dissipate heat from heat-generating components such as central processing units (CPU). A conventional flat heat pipe includes a hollow cover, a continuous wick structure mounted on an inner surface of the cover and working medium contained in the wick structure. A vapor chamber is defined between an inner surface of the wick structure. When the cover absorbs heat generated from the heat-generating components, the working medium is vaporized by the heat and enters into the vapor chamber in all directions of the inner surface of the wick structure. Therefore, the vaporized working medium from different directions of the wick structure tends to interfere with each other and forms turbulence. Thus, heat dissipation efficiency and stability performance of the flat heat pipe are badly affected.

What is needed is a flat heat pipe which can overcome the problem of the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a flat heat pipe along a transverse direction thereof in accordance with an embodiment of the disclosure.

FIG. 2 is a schematic view of the flat heat pipe of FIG. 1 along a longitudinal direction thereof.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a flat heat pipe 1 in accordance with an embodiment of the disclosure includes a hollow cover 10, a restricting plate 30 received in the cover 10 and abutting against the cover 10, a wick structure 50 mounted on the restricting plate 30, and a working medium (not shown) contained in the wick structure 50. The flat heat pipe 1 is used to thermally connect with heat-generating components (not shown) to absorb heat generated therefrom.

The cover 10 is integrally formed by one piece of metal such as copper or brass. The cover 10 includes an elongated top plate 11, an elongated bottom plate 13 spaced from and facing the top plate 11, and two convex connecting plates 15 located at lateral sides of the flat heat pipe 1 and interconnecting lateral edges of the top and bottom plates 11, 13, respectively. A distance between outer surfaces of the top and bottom plates 11, 13 varies between 0.8 millimeter and 2.0 millimeter. The top plate 11, the bottom plate 13 and the connecting plates 15 cooperatively define a receiving chamber 17 therebetween.

The wick structure 50 is a screen made of wires mesh or a sintered body sintered by metal powder. The wick structure 50 is an elongated strip and located at a central portion of the receiving chamber 17 along a longitudinal direction of the cover 10. Top and bottom ends of the wick structure 50 abut against central portions of the top plate 11 and the bottom plate 13, respectively. A transverse section of the wick structure 50 is substantially “II” shaped. The wick structure 50 includes a neck portion 51 and two adhering portions 53 located at top and bottom ends of the neck portion 51, respectively. The neck portion 51 has a length along the longitudinal direction of the cover 10 equal to that of each adhering portion 53, and a width along a transverse direction of the cover 10 less than that of each adhering portion 53. The neck portion 51 connects central portions of the adhering portions 53. The adhering portions 53 are respectively adhered to the central portions of the top and bottom plates 11, 13. A capillary force of the adhering portion 53 is larger than that of the necking portion 51. One of the adhering portions 53 and the necking portion 51 cooperatively form a bugle-shaped configuration. Edges of the wick structure 50 are rounded. Therefore a contacting area of the wick structure 50 contacting the vaporized working medium is increased relative to the conventional wick structure without rounded edges.

The restricting plate 30 is elongated, and made of a material having good heat transferring performance and compressive capacity, such as metal. The restricting plate 30 has a length along the longitudinal direction of the cover 10 equal to that of the receiving chamber 17. A height of the restricting plate 30 is equal to a distance between inner surfaces of the top and bottom plates 11, 13. The restricting plate 30 is arranged in a middle of the receiving chamber 17 along the longitudinal direction of the cover 10. Top and bottom ends of the restricting plate 30 abut against the inner surface of the top plate 11 and the bottom plate 13, respectively. The restricting plate 30 divides the receiving chamber 17 into a first passage 171 and a second passage 173 along the longitudinal direction of the cover 10. The first passage 171 and the second passage 173 are hermetical and not in communication with each other. The restricting plate 30 divides the wick structure 50 into two wick portions 55 along a longitudinal direction of the wick structure 50. The two wick portions 55 are symmetrical relative to restricting plate 50 and adhered on opposite lateral surface of the restricting plate 30, respectively. The two wick portions 55 are located in the first and second passages 171, 173, and at inner lateral sides of the first and second passage 171, 173, respectively.

Referring also to FIG. 2, in operation, when one end, i.e. an evaporating section, of the flat heat pipe 1, absorbs heat generated from the heat-generating components, the working medium in the wick portions 55 of the wick structure 50 in the evaporating section is vaporized by the absorbed heat and enters into the first passage 171 and the second passage 173 from the inner lateral sides of the first passage 171 and the second passage 173, respectively. The vaporized working medium flows individually along the first passage 171 and the second passage 173 to another end of the flat pipe heat pipe 1, i.e. a condensing section opposite to the evaporating section, to release heat thereof. After the vaporized working medium releases its heat and condenses in the condensing section, the condensed working medium is returned by the wick portions 55 to the evaporating section, where the condensed working medium is again available for evaporation and goes on a phase-change circulation.

Referring to FIG. 1 again, in this embodiment, the width of the adhering portion 53 is larger than that of the necking portion 51. The capillary force of the adhering portions 53 is larger than the necking portion 51. Therefore, during operation, the working medium condensed on the top plate 11 can be rapidly absorbed by the adhering portion 53 mounted on the top plate 11 and flow towards the neck portion 51, and then the condensed working medium in the neck portion 51 can be rapidly guided back the bottom plate 13 via the adhering portion 53 mounted on the bottom plate 13 to avoid the flat heat pipe 1 overheating.

In addition, the vaporized work medium enters into the first passage 171 and the second passage 173 only from the lateral sides of the first passage 171 and the second passage 173, so the vaporized work medium enters into the first passage 171 or the second passage 173 in a smaller angle relative to the conventional flat heat pipe. Thus, interference between the vaporized work medium in the first passage 171 or the second passage 173 is decreased relative to the conventional flat heat pipe. A probability of forming turbulence of the vaporized work medium is decreased. Furthermore, a stability of the flat heat pipe 1 is also improved via opposite ends of the restricting plate 30 abutting the top plate 11 and the bottom plate 13, simultaneously.

It is believed that the disclosed embodiment(s) and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure. 

What is claimed is:
 1. A flat heat pipe comprising: a cover defining a receiving chamber therein; a wick structure received in the receiving chamber; and a restricting plate received in the receiving chamber and opposite ends thereof abutting against opposite inner surfaces of the cover to divide the receiving chamber into two passages; wherein the restricting plate divides the wick structure into two wick portions, the wick portions are adhered on opposite lateral surfaces of the restricting plate and located at lateral sides of two passages, respectively.
 2. The flat heat pipe as described in claim 1, wherein the wick portions are symmetrical relative to the restricting plate.
 3. The flat heat pipe as described in claim 1, wherein each of the two passages is a hermetical chamber, and the two passages are not in communication with each other.
 4. The flat heat pipe as described in claim 3, wherein the cover comprises an elongated top plate, an elongated bottom plate spaced from the top plate and two connecting plate connecting lateral edges of the top plate and the bottom plate, the top plate, the bottom plate and the connecting plate cooperatively define the receiving chamber therebetween, and the restricting plate abuts against the top plate and the bottom plate to divide the receiving chamber to the two passages along a longitudinal direction of the cover.
 5. The flat heat pipe as described in claim 4, wherein the restricting plate is elongated and made of a material having good heat transferring performance and compressive capacity.
 6. The flat heat pipe as described in claim 4, wherein the wick structure is located at a central portion of the receiving chamber along the longitudinal direction of the cover and opposite ends thereof abut against central portions of the top plate and the bottom plate.
 7. The flat heat pipe as described in claim 6, wherein the wick structure comprises a neck portion and two adhering portions located at top and bottom ends of the neck portion, the adhering portion is larger than the necking portion, and the two adhering portions respectively adhere to the central portions of the top plate and the bottom plate.
 8. The flat heat pipe as described in claim 4, wherein a distance between outer surfaces of the top plate and the bottom plate is varies between 0.8 mm to 2.0 mm.
 9. The flat heat pipe as described in claim 1, wherein edges of the wick structure are rounded.
 10. A flat heat pipe comprising: a cover comprising a top plate, a bottom plate spaced the top plate and two connecting plates connecting lateral edges of the top plate and the bottom plate, the top plate, the bottom plate and the connecting plates cooperatively defining a receiving chamber therein; two wick portions received in the receiving chamber and opposite ends thereof abutting central portions of the top plate and the bottom plate; and a restricting plate received in the receiving chamber and opposite ends thereof abutting against the top plate and the bottom plate to divide the receiving chamber into two passages, lateral surfaces of the restricting plate respectively facing the passages; wherein the two wick portions are adhered on the lateral surfaces of the restricting plate and located at the two passages, respectively.
 11. The flat heat pipe as described in claim 10, wherein each of the two passages is a hermetical chamber, and the two passages are in not communication with each other.
 12. The flat heat pipe as described in claim 10, wherein the restricting plate is elongated and made of a material having good heat transferring performance and compressive capacity.
 13. The flat heat pipe as described in claim 10, wherein the wick portions are symmetrical relative to the restricting plate.
 14. The flat heat pipe as described in claim 10, wherein each wick portion is a screen made of wires mesh or a sintered body sintered by metal powder.
 15. The flat heat pipe as described in claim 10, wherein the cover is integrally formed by one piece. 